5.
A look in detail:
Let’s now look at moist savannas more in detail
considering the dynamical interactions between
their components.

6.
Moist savannas: seasonality
Wet season
In the wet season abundant rainfall allows the
accumulation of grass

7.
Moist savannas
Wet season Dry season
In the dry season grass dries out and becomes fuel for
fires. Fires usually kill juvenile trees.

8.
Research question
Is fire alone able to stop the closure of the canopy
in moist savannas?
We explore with a simulation model some
ecological mechanisms related to:
• Space
• Tree life history traits

9.
GRASSFIRE
TREES
Concepts
We model the dynamic interactions between these
elements:
In particular we include the role of space and tree life
history traits

15.
INITIALIZATIO
N
TREE
GROWTH
GRASS
GROWTH
FIRE SPREAD
TREE
MORTALITY
GROWTHseasonDRYseason
Trees have a
probability to go to
an upper height
class each growth
season
Spatial competition
between tree and tree
is accounted for
Model description
New tree seedlings
are introduced in the
spatial domain

38.
Take-home messages
Once trees invade, fires disappear from the
ecosystem and the process is not reversible (with
the elements considered in the model)

39.
Take-home messages
Tree-grass co-existence can be:
A transient state of the ecosystem
Due to strong spatial competition between trees
Due to other mechanisms not included in the model
0 20001000 1500500
20
40
60
80
100
Mean annual rainfall [mm/yr]
Woodycover[%]